This invention relates in general to ballistic reentry bodies and, in particular, to a reentry body employing a forward heatshield of carbon-carbon composite material and an aft heatshield of carbon-phenolic material.
Advanced reentry bodies having higher ballistic coefficients have more stringent thermal and mechanical requirements. The current carbon-phenolic composite heatshields could become unacceptable because of an expected increase in sudden char loss causing a corresponding decrease in vehicle accuracy. Ground and flight testing have demonstrated the superiority of carbon-carbon composites for erosion and ablation resistance.
One solution is to replace the forward heatshield, which experiences the most severe thermal and aerodynamic conditions, with a heatshield of carbon-carbon material that will minimize char loss and maximize damping of angle-of-attack dispersions. The aft heatshield remains constructed of carbon-phenolic material. However, because the thermal expansion characteristics of carbon/carbon composites differ from the thermal expansion characteristics of carbon-phenolic composites and the forward heat shield experiences much greater heating, the method of attachment of the forward heatshield presents a special problem. In particular, the joint design between the forward carbon-carbon heatshield and the aft carbon-phenolic heat shield must allow free expansion of the carbon-carbon material while providing continuous support during flight.